Generally, a display device comprises control means for saving consumption power. In one approach, the control means may be implemented by a DPMS, proposed by Video Electronics Standard Association (VESA) in U.S.A.
The DPMS functions to manage power of a display device, which is one of the peripheral devices of a computer, according to a used state of the computer to save the power.
In conformity with the VESA, the computer selectively supplies or blocks horizontal and vertical synchronous signals to the display device according to its used state, and the display device manages power according to the presence of the horizontal and vertical synchronous signals from the computer.
The power management states are classified into an on state, a stand-by state, a suspend state and a power off state. Both the horizontal and vertical synchronous signals are applied at the on state, and only the vertical synchronous signal is applied at the stand-by state. Only the horizontal synchronous signal is applied at the suspend state, and either the horizontal or vertical synchronous signal is not applied at the power off state.
The power management state is sequentially changed to the on state stand-by state suspend state power off state with the continuous lapse of unused time of the computer. It is commonly prescribed that consumption power of the display device be about 80W at the on state, 65W or less at the stand-by state, 25W or less at the suspend state and 5W or less at the power off state.